Write a regression test for a pipe hang

[metan-ucw]

Details at:

https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/

https://www.spinics.net/lists/linux-api/msg49762.html

[coolgw]

Use https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/ running on 6.2.0-rc4+, the system also hang.

[Martchus]

This is a draft: https://github.com/linux-test-project/ltp/compare/master...Martchus:ltp:pipe15-1?expand=1

I'll send the patch when I think it is ready. I'm currently wondering how to deal with the situation when the test is run with a low RLIMIT_NOFILE. Should I add an explicit check for EMFILE and exit early with TCONF? Currently the test would exist with TBROK.

[Martchus]

https://patchwork.ozlabs.org/project/ltp/list/?series=374703